System on integrated chips and methods of forming same

ABSTRACT

An embodiment method for forming a semiconductor package includes attaching a first die to a first carrier, depositing a first isolation material around the first die, and after depositing the first isolation material, bonding a second die to the first die. Bonding the second die to the first die includes forming a dielectric-to-dielectric bond. The method further includes removing the first carrier and forming fan-out redistribution layers (RDLs) on an opposing side of the first die as the second die. The fan-out RDLs are electrically connected to the first die and the second die.

PRIORITY

This application is a continuation of U.S. application Ser. No.15/379,590, filed on Dec. 15, 2016, which is a continuation of U.S.application Ser. No. 14/960,225, filed on Dec. 4, 2015, entitled “Systemon Integrated Chips and Methods of Forming Same,” now U.S. Pat. No.9,524,959, issued Dec. 20, 2016, which claims the benefit of U.S.Provisional Application No. 62/250,963, filed on Nov. 4, 2015 entitled“System on Integrated Chips and Methods of Forming Same,” whichapplications are hereby incorporated herein by reference.

BACKGROUND

The semiconductor industry has experienced rapid growth due tocontinuous improvements in the integration density of a variety ofelectronic components (e.g., transistors, diodes, resistors, capacitors,etc.). For the most part, this improvement in integration density hascome from repeated reductions in minimum feature size (e.g., shrinkingthe semiconductor process node towards the sub-20 nm node), which allowsmore components to be integrated into a given area. As the demand forminiaturization, higher speed and greater bandwidth, as well as lowerpower consumption and latency has grown recently, there has grown a needfor smaller and more creative packaging techniques of semiconductordies.

As semiconductor technologies further advance, stacked semiconductordevices, e.g., 3D integrated circuits (3DIC), have emerged as aneffective alternative to further reduce the physical size of asemiconductor device. In a stacked semiconductor device, active circuitssuch as logic, memory, processor circuits and the like are fabricated ondifferent semiconductor wafers. Two or more semiconductor wafers may beinstalled on top of one another to further reduce the form factor of thesemiconductor device.

Two semiconductor wafers or dies may be bonded together through suitablebonding techniques. The commonly used bonding techniques include directbonding, chemically activated bonding, plasma activated bonding, anodicbonding, eutectic bonding, glass frit bonding, adhesive bonding,thermo-compressive bonding, reactive bonding and/or the like. Anelectrical connection may be provided between the stacked semiconductorwafers. The stacked semiconductor devices may provide a higher densitywith smaller form factors and allow for increased performance and lowerpower consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1 through 9 and 10A through 10C illustrate cross-sectional viewsvarious intermediary stages of forming a semiconductor package inaccordance with some embodiments.

FIGS. 11A and 11B illustrate cross-sectional views of semiconductorpackages having dummy dies in accordance with some embodiments.

FIG. 12 illustrates a cross-sectional view of a semiconductor packagehaving a conformal isolation material in accordance with someembodiments.

FIG. 13 illustrates a cross-sectional view of a semiconductor packagehaving exposed dies in accordance with some other embodiments.

FIGS. 14 through 19 illustrate cross-sectional views variousintermediary stages of forming a semiconductor package in accordancewith some other embodiments.

FIGS. 20 through 24 illustrate cross-sectional views variousintermediary stages of forming a semiconductor package in accordancewith some other embodiments.

FIGS. 25A and 25B illustrate cross-sectional views of semiconductorpackages having dummy dies in accordance with some embodiments.

FIGS. 26 through 30 illustrate cross-sectional views variousintermediary stages of forming a semiconductor package in accordancewith some other embodiments.

FIGS. 31 through 35 illustrate cross-sectional views variousintermediary stages of forming a semiconductor package in accordancewith some other embodiments.

FIGS. 36A and 36B illustrate cross-sectional views of semiconductorpackages having dummy dies in accordance with some embodiments.

FIGS. 37 through 42 illustrate cross-sectional views variousintermediary stages of forming a semiconductor package in accordancewith some other embodiments.

FIGS. 43 through 50 illustrate cross-sectional views variousintermediary stages of forming a semiconductor package in accordancewith some other embodiments.

FIG. 51 illustrates a process flow for forming a semiconductor packagein accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Various embodiments include methods and corresponding structures forforming a semiconductor device package. Various embodiments integratemultiple functional chips in a single device package and implementsChip-to-Wafer (e.g., known good die) for Chip-on-Wafer (CoW) levelpackaging. Functional chips may be directly bonded to other functionalchips using bonding layers (e.g., by fusion bonding and/or hybridbonding) in order to reduce the need to form solder bumps (e.g.,microbumps) and underfill. Various embodiments may furtheradvantageously provide a system-in-package (SiP) solution with smallerform factor, increased input/output density, and low via aspect ratio.Thus, manufacturing errors and costs can be reduced.

FIGS. 1 through 10A illustrate various cross-sectional views ofintermediary stages of forming a semiconductor package 100 in accordancewith an embodiment. Referring first to FIG. 1, a cross-sectional view ofa device die 102A is provided. Die 102A may be a known good die (KGD),for example, which may have passed various electrical and/or structuraltests. Die 102A may be a semiconductor die and could be any type ofintegrated circuit, such as an application processor, logic circuitry,memory, analog circuit, digital circuit, mixed signal, and the like. Die102A may include a substrate 104A and an interconnect structure 106Aover substrate 104A. Substrate 104A may comprise, for example, bulksilicon, doped or undoped, or an active layer of asemiconductor-on-insulator (SOI) substrate. Generally, an SOI substratecomprises a layer of a semiconductor material, such as silicon, formedon an insulator layer. The insulator layer may be, for example, a buriedoxide (BOX) layer or a silicon oxide layer. The insulator layer isprovided on a substrate, such as a silicon or glass substrate.Alternatively, the substrate may include another elementarysemiconductor, such as germanium; a compound semiconductor includingsilicon carbide, gallium arsenic, gallium phosphide, indium phosphide,indium arsenide, and/or indium antimonide; an alloy semiconductorincluding SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and/or GaInAsP; orcombinations thereof. Other substrates, such as multi-layered orgradient substrates, may also be used.

Active devices (not illustrated) such as transistors, capacitors,resistors, diodes, photo-diodes, fuses, and the like may be formed atthe top surface of substrate 104A. Interconnect structure 106A may beformed over the active devices and a front side of substrate 104A. Theterm “face” or “front” surface or side is a term used herein implyingthe major surface of the device upon which active devices andinterconnect layers are formed. Likewise, the “back” surface of a die isthat major surface opposite to the face or front.

The interconnect structure may include inter-layer dielectric (ILD)and/or inter-metal dielectric (IMD) layers 108A containing conductivefeatures 110A (e.g., conductive lines and vias comprising copper,aluminum, tungsten, combinations thereof, and the like) formed using anysuitable method. The ILD and IMD layers 108A may include low-kdielectric materials having k values, for example, lower than about 4.0or even 2.0 disposed between such conductive features. In someembodiments, the ILD and IMD layers 108A may be made of, for example,phosphosilicate glass (PSG), borophosphosilicate glass (BPSG),fluorosilicate glass (FSG), SiO_(x)C_(y), Spin-On-Glass,Spin-On-Polymers, silicon carbon material, compounds thereof, compositesthereof, combinations thereof, or the like, formed by any suitablemethod, such as spinning, chemical vapor deposition (CVD), andplasma-enhanced CVD (PECVD). Interconnect structure 106A electricallyconnects various active devices to form functional circuits within die102A. The functions provided by such circuits may include logicstructures, memory structures, processing structures, sensors,amplifiers, power distribution, input/output circuitry, or the like. Oneof ordinary skill in the art will appreciate that the above examples areprovided for illustrative purposes only to further explain applicationsof various embodiments and are non-limiting. Other circuitry may be usedas appropriate for a given application.

Additional features, such as input/output (I/O) contacts, passivationlayers, conductive pillars, and/or under bump metallurgy (UBM) layers,may also be optionally formed over interconnect structure 106A. Thevarious features of die 102A may be formed by any suitable method andare not described in further detail herein. Furthermore, the generalfeatures and configuration of die 102A described above are but oneexample embodiment, and die 102A may include any combination of anynumber of the above features as well as other features.

As further illustrated by FIG. 1, die 102A is attached to a carrier 112.Die 102A may be oriented on carrier 112 so that a backside of substrate104A is exposed. Generally, carrier 112 provides temporary mechanicaland structural support various features (e.g., die 102A) duringsubsequent processing steps. In this manner, damage to the device diesis reduced or prevented. Carrier 112 may comprise, for example, glass,ceramic, and the like. In an embodiment, release layer 114 is used toattach die 102A to carrier 112. In some embodiments, carrier 112 may besubstantially free of any active devices and/or functional circuitry.Release layer 114 may be any suitable adhesive, such as an ultraviolet(UV) glue, or the like. In another embodiment, carrier 112 may comprisebulk silicon, and die 102A may be attached to carrier 112 by adielectric release layer 114. Die 102A may have an initial thickness T1of about 700 μm to about 800 μm, for example.

In FIG. 2, a thinning process is applied to die 102A in order to reducean overall thickness of die 102A to a desired thickness T2. In someembodiments, thickness T2 may be less than about 100 μm or less thanabout 10 μm, for example. In other embodiments, thickness T2 may bedifferent depending on device design. The thinning process may includeapplying a mechanical grinding process, a chemical mechanical polish(CMP), an etch back process, or the like to substrate 104A of die 102A.

Subsequently, in FIG. 3, an isolation material 116 is formed around die102A. Isolation material 116 extends along sidewalls of die 102A, and ina top-down view (not shown), isolation material 116 may encircle die102A. Isolation material 116 may comprise a molding compound, a polymermaterial, a dielectric material, combinations thereof, or the like. Theexact material used for isolation material 116 may be selected based onthe thickness T2 of die 102A (see FIG. 2). For example, a thinner die102A may allow for a dielectric material to be used for isolationmaterial 116, which may advantageously provide improved process control,lower manufacturing costs, and reduced co-efficient of thermal expansion(CTE) mismatch, which advantageously reduces warpage in the resultingpackage. As another example, a polymer material or even a moldingcompound may be used for a thicker die 102A in order to provide improvedstructural support.

In embodiments where isolation material 116 comprises a dielectricmaterial, isolation material 116 comprises an oxide, nitride,combinations thereof, or the like. In such embodiments, the oxide ornitride insulating film may include a silicon nitride, silicon oxide,silicon oxynitride, or another dielectric material, and is formed byCVD, PECVD, or another process.

In embodiments where isolation material 116 comprises a molding compoundor a polymer, isolation material 116 may be shaped or molded using forexample, a mold (not shown), which may have a border or other featurefor retaining isolation material 116 when applied. Such a mold may beused to pressure mold the isolation material 116 around the die 102A toforce isolation material 116 into openings and recesses, eliminating airpockets or the like in isolation material 116. Subsequently, a curingprocess is performed to solidify isolation material 116. In suchembodiments, isolation material 116 comprises an epoxy, a resin, amoldable polymer such as PBO, or another moldable material. For example,isolation material 116 is an epoxy or resin that is cured through achemical reaction or by drying. In another embodiment, the isolationmaterial 116 is an ultraviolet (UV) cured polymer. Other suitableprocesses, such as transfer molding, liquid encapsulent molding, and thelike, may be used to form isolation material 116.

After isolation material 116 is formed around die 102A, isolationmaterial 116 is reduced or planarized by, for example, grinding, CMP,etching, or another process. For example, where isolation material 116is an insulating film such as an oxide or nitride, a dry etch or CMP isused to reduce or planarize the top surface of the isolation material116. In some embodiments, isolation material 116 is reduced so that die102A is exposed, resulting in a backside surface of substrate 104A thatis substantially planar with a top surface if isolation material 116.

FIG. 4 illustrates the formation of a bonding layer 118 over die 102Aand isolation material 116. Bonding layer 118 may comprise a dielectricmaterial, such as silicon oxide although another suitable material maybe used as well. Bonding layer 118 may be formed by chemical vapordeposition (CVD), plasma enhanced CVD (PECVD), combinations thereof, orthe like.

After bonding layer 118 is formed, additional dies (e.g., dies 102B and102C) may be bonded to die 102A. Bonding dies 102B and 102C may includea fusion bonding process where a dielectric layer of dies 102B/102C isdirectly bonded to bonding layer 118 to form a dielectric-to-dielectricbond. Thus, the need for solder joints (or other external connectors)for bonding dies in embodiment packages is reduced, which reducesmanufacturing defects and cost. Dies 102B and 102C may be substantiallysimilar to die 102A. For example, dies 102B and 102C may each comprise asemiconductor substrate 104B/104C, active devices (not shown) formed ata top surface of substrates 104B/104C, and interconnect structures106B/106C formed over substrates 104B/104C. Interconnect structures106B/106C electrically connect the active devices to for functionalcircuits, which may provide a same or different function as thecircuitry in die 102A. For example, die 102A may include logic circuitrywhile dies 102B and 102C may include memory circuitry. Dies 102B and102C may have a thickness T3 of about 700 μm to about 800 μm. AlthoughFIG. 4 illustrates dies 102B and 102C having a same thickness, in otherembodiments, dies 102B and 102C may have different thicknesses.Furthermore, dies 102B and 102C may occupy a same or different footprintcompared to die 102A. For example, in the illustrated embodiment,portions of dies 102B and/or 102C extend laterally past sidewalls of die102A and may be disposed directly over isolation material 116.

In FIG. 5, dies 102B and 102C may be thinned to a desired thickness T4.In some embodiments, thickness T4 may be less than about 100 μm or less,such as, about 50 μm or 10 μm, for example. Thicknesses of dies 102A,102B, and 102C may or may not be the same. The thinning process mayinclude applying a mechanical grinding process, CMP, an etch backprocess, or the like.

Next, in FIG. 6, an isolation material 120 is formed around dies 102Band 102C. Isolation material 120 extends along sidewalls of dies 102Band 102C, and in a top down view (not shown), isolation material mayencircle both dies 102B and 102C. In various embodiments, isolationmaterial 120 may be similar to isolation material 116 as describedabove. For example, isolation material 120 may comprise a dielectricmaterial (e.g., an oxide, a nitride, or the like), a polymer, a moldingcompound, or the like, which may be selected based on the thickness T4of dies 102B and 102C. Furthermore, isolation material 120 may comprisea same or different material as isolation material 116. After isolationmaterial 120 is deposited, a planarization process (e.g., CMP, etchback, grinding, or the like) may be applied so that top surfaces ofisolation material 120, die 102B, and die 102C may be substantiallylevel. In another embodiment, isolation material 120 may remain disposedover dies 102B and 102C even after planarization (see e.g., FIG. 10C).

After isolation material 120 is formed, a second carrier 122 may beattached to a top surface of die 102B, die 102C, and isolation material120 by a release layer 123. Carrier 122 and release layer 123 may besubstantially similar to carrier 110 and release layer 112 as describedabove. For example, carrier 122 may comprise glass, ceramic, bulksilicon, or the like while release layer 123 comprises a DAF, adielectric material, or the like. After carrier 122 is attached, thefirst carrier 110 may be removed from surfaces of die 102A and isolationmaterial 116. Removing the carrier 110 may include applying UV radiationto release layer 114, a mechanical grinding process, an etch backprocess, combinations thereof, or the like. The resulting structure isillustrated in FIG. 7.

Referring to FIG. 8, an orientation of package 100 is flipped (e.g., sothat carrier 122 is disposed below dies 102B and 102C), and through-vias124 (sometimes referred to as through-dielectric vias (TDVs)) are formedin package 100. Flipping package 100 may further expose a front side ofdie 102A. Through-vias 124 may extend through isolation material 116 andbonding layer 118 to electrically connect to conductive features 110B indie 102B and/or conductive features 110C in die 102C. Formingthrough-vias 124 may include a damascene process. For example, openingsmay be patterned in various layers in package 100 using a combination ofphotolithography and/or etching. The openings may expose variousconductive features 110B and/or 110C. A conductive material may bedeposited in the opening's (e.g., using electroless plating,electrochemical plating, or the like). In some embodiments, theconductive material may overfill the openings, and a planarizationprocess (e.g., CMP) may be applied to remove excess conductive materialand form through-vias 124.

In FIG. 9, fan-out redistribution layers (RDLs) 126 may be formed overisolation material 116 and die 102A. RDLs 126 may extend laterally pastedges of die 102A over a top surface of isolation material 116. RDLs 126may include conductive features 128 formed in one or more polymer layers130. Polymer layers 130 may be formed of any suitable material (e.g.,polyimide (PI), polybenzoxazole (PBO), benzocyclobuten (BCB), epoxy,silicone, acrylates, nano-filled pheno resin, siloxane, a fluorinatedpolymer, polynorbornene, and the like) using any suitable method, suchas, a spin-on coating technique, lamination, and the like.

Conductive features 128 (e.g., conductive lines 128A and/or vias 128B)may be formed in polymer layers 130 and electrically connect to dies102B/102C (e.g., by through-vias 124) as well as interconnect structure106A of die 102A. The formation of conductive features 128 may includepatterning polymer layers 130 (e.g., using a combination ofphotolithography and/or etching processes) and forming conductivefeatures over and in the patterned polymer layer. For example,conductive features 128 may further include depositing a seed layer (notshown), using a mask layer (not shown) having various openings to definethe shape of conductive features 128, and filling the openings in themask layer using an electro-chemical plating process, for example. Themask layer and excess portions of the seed layer may then be removed.The number of polymer layers and conductive features of RDLs 126 is notlimited to the illustrated embodiment of FIG. 9. For example, RDLs 126may include any number of stacked, electrically connected conductivefeatures in multiple polymer layers.

As further illustrated by FIG. 9, additional I/O features are formedover RDLs 126. For example, external connectors 132 (e.g., BGA balls, C4bumps, and the like) may be formed over RDLs 126. Connectors 132 may bedisposed on UBMs 134, which may also be formed over RDLs 126. Connectors132 may be electrically connected to dies 102A, 102B, and 102C by RDLs126. Connectors 132 may be used to electrically connect package 100 toother package components such as another device die, interposers,package substrates, printed circuit boards, a mother board, and thelike.

Subsequently, carrier 122 may be removed as illustrated in FIG. 10A. Asfurther illustrated in FIG. 10A, an orientation of package 100 may bereversed to expose carrier 122 (see FIG. 9). In the reversedorientation, connectors 132 may be attached to a temporary support frame136 (e.g., comprising a support tape) while carrier 122 is removed.Carrier 122 may be removed using any suitable process. For example, whenrelease layer 123 comprises a UV glue, release layer 123 may be exposedto a UV source to remove carrier 122. In another embodiment, an etchback, grinding, or other process may be used to remove carrier 122. Inother embodiments (e.g., as illustrated by FIG. 10B), carrier 122 maythinned without being completely removed. For example, carrier 122 maycomprise silicon, and a reduced carrier 122 may remain in the resultingpackage 100B. In such embodiments, remaining portions of carrier 122 beused as a heat dissipation feature in package 100B. Furthermore, inpackage 100, surfaces of dies 102B and 102C are exposed. In otherembodiments (e.g., as illustrated by FIG. 10C), dies 102B and 102C maybe fully covered by isolation material 120, and isolation material 120may be disposed on a back surface of dies 102B and 102C in package 100C.

FIGS. 11A and 11B illustrate cross-sectional views of packages 200A and200B according to some embodiments. Packages 200A and 200B may besimilar to package 100 where like reference numerals indicate likeelements. Packages 200A and 200B include dummy dies 202 adjacent one ormore functional device dies (e.g., dies 102B and 102C). In theembodiment package 200A illustrated by FIG. 11A, dummy die 202 has asame thickness as dies 102B/102C. In the embodiment package 200Billustrated by FIG. 11B, dummy die 202 has a different thickness thandies 102B/102C. Compared to functional dies 102A/102B/102C, whichcomprise functional circuitry, dummy dies 202 may be substantially freeof any active devices, functional circuits, or the like. For example,dummy dies 202 may include a substrate 204 (e.g., a bulk siliconsubstrate) and a dielectric, bonding layer 206. Bonding layer 206 may beused to bond dummy dies 202 to bonding layer 118 using a fusion bondingprocess, for example. In some embodiments, dummy dies 202 are includedfor improved uniformity in a device layer, which may result in improvedplanarization. Dummy dies 202 may also be included to reduce CTEmismatch amongst various features in packages 200A and 200B.

FIG. 12 illustrates a cross-sectional view of a package 300 according tosome embodiments. Package 300 may be similar to package 100 where likereference numerals indicate like elements. In package 300, isolationmaterial 120 comprises a dielectric material (e.g., an oxide, nitride,or the like), and isolation material 120 may be deposited as a conformallayer using a suitable process (e.g., CVD, PECVD, and the like). Forexample, a portion of isolation material 120 on a top surface of bondinglayer 118 may have a substantially same thickness as a portion ofisolation material 120 on sidewalls of dies 102B/102C. After isolationmaterial 120 is deposited, a planarization process may be applied toexpose dies 102B/102C. Subsequently, carrier 122 is attached to dies102B/102C by release layer 123 (e.g., a dielectric layer). Becauseisolation material 120 is a conformal layer, cavities 302 (e.g.,comprising air) may be formed between carrier 122 and isolation material120. In package 300, at least a portion of carrier 122 may remain in thecompleted package as a heat dissipation feature. In other embodiments,carrier 122 may be removed and omitted from the completed package.

FIG. 13 illustrates a cross-sectional view of a package 400 according tosome embodiments. Package 400 may be similar to package 100 where likereference numerals indicate like elements. In package 400, isolationmaterial 120 (see e.g., FIG. 10A) may be omitted. For example, sidewallsand back surfaces of dies 102B and 102C may be exposed in the completedpackage 400. In another embodiment, additional features (e.g., heatdissipation features) may be formed on directly a back surface and/orsidewalls of dies 102B and 102C.

FIGS. 14 through 19 illustrate cross-sectional views of intermediarystages of forming a semiconductor package 500 in accordance with anembodiment. Package 500 in FIG. 14 may be substantially similar topackage 100 in FIG. 5 where like reference numerals indicate likeelements. For example, dies 102B and 102C may be directly bonded (e.g.,fusion bonded) to a bottom fan-out structure (die 102A and isolationmaterial 116) by a bonding layer 118. The various intermediary steps offorming package 500 in FIG. 14 may be substantially similar to theprocess described above with respect to FIGS. 1 through 5, andadditional description is omitted herein for brevity.

Referring next to FIG. 15, an isolation material 120 is formed on abackside and along sidewalls of dies 102B and 102C. Isolation material120 may further be deposited as a conformal layer using a suitableprocess (e.g., CVD, PECVD, and the like). For example, a portion ofisolation material 120 on a top surface of bonding layer 118 may have asubstantially same thickness as a portion of isolation material 120 onsidewalls of dies 102B/102C. In some embodiments, a thickness ofisolation material 120 in package 500 may be about 1 μm to about 20 μm.In some embodiments, isolation material 120 may be included to reduceCTE mismatch between different fan-out portions (e.g., portions ofpackage 500 opposing bonding layer 118).

After isolation material 120 is formed, a carrier 122 may be attached toa top surface isolation material 120 by a release layer 123 asillustrated by FIG. 16. In an embodiment, carrier 122 may compriseglass, ceramic, bulk silicon, or the like while release layer 123comprises a DAF, a dielectric material, or the like. Release layer 123may be blanket deposited to fill caps between dies 102B and 102C using,for example, a spin-on process. A surface of release layer 123 oppositeisolation material 120 may be substantially level (e.g., planarized) toprovide a suitable surface for carrier 122 to adhere to. In someembodiments, release layer may comprise a glue layer or other suitablematerial for filling gaps between dies 102B and 102C. After carrier 122is attached, the first carrier 110 may be removed from surfaces of die102A and isolation material 116.

Next in FIG. 17, an orientation of package 500 is reversed so thatpackage 500 is disposed over carrier 122 and release layer 123. Afterpackage 500 is flipped, various additional features, such as, throughvias (TVs) 124, RDLs 126, UBMs 134, and connectors 132 are formed overdies 102A, 102B, and 102C as described above. In some embodiments, TVs124 has a relatively low aspect ratio (e.g., a ratio of a height to awidth of TV 124). For example, the aspect ratio of TVs 124 may be lessthan 5, which advantageously reduce manufacturing defects (e.g., gaps).RDLs 126 may extend past edges of die 102A onto a top surface ofisolation material 116. RDLs 126 may be electrically connected to die102A as well as dies 102B and 102C (e.g., by TVs 124). Externalconnectors 132 are electrically connected to dies 102A, 102B, and 102Cby RDLs 126.

Subsequently, carrier 122 may be removed as illustrated in FIG. 18. Asfurther illustrated in FIG. 18, an orientation of package 500 may bereversed to expose carrier 122 (see FIG. 17). In the reversedorientation, connectors 132 may be attached to a temporary support frame136 (e.g., comprising a support tape) while carrier 122 is removed.Carrier 122 may be removed using any suitable process. For example, whenrelease layer 123 comprises a UV glue, release layer 123 may be exposedto a UV source to remove carrier 122. After carrier 122 is removed,isolation material 120 is exposed.

In FIG. 19, an additional isolation material 502, such as a moldingcompound or polymer, is formed over isolation material 120. Isolationmaterial 502 may fill gaps between dies 102B and 102C. Isolationmaterial 502 may be dispensed in liquid form and cured as describedabove. Furthermore, a planarization process (e.g., CMP, mechanicalgrinding, etch back, and the like) may be applied to a surface ofisolation material 502 opposite isolation material 120. Isolationmaterial 502 may be included to provide additional structural support topackage 500, which allows isolation material 120 to be included evenwhen dies 102B and 102C are relatively thick.

FIGS. 20 through 24 illustrate cross-sectional views of intermediarystages of forming a semiconductor package 600 in accordance with anembodiment. Package 600 in FIG. 20 may be substantially similar topackage 100 after forming bonding layer 118 where like referencenumerals indicate like elements. For example, a dielectric bonding layer118 (e.g., an oxide layer) may be deposited over die 102A and isolationmaterial 116. The various intermediary steps of forming package 600 inFIG. 20 may be substantially similar to the process described above withrespect to FIGS. 1 through 4, and additional description is omittedherein for brevity.

In FIG. 21, conductive features 602 are formed in bonding layer 118. Insome embodiments, conductive features 602 are formed using a damasceneprocess where openings are etched into bonding layer 118, the openingsare filled with a conductive material, and a planarization process isused to remove excess conductive material over bonding layer 118. Inanother embodiment, a seed layer (not shown) is deposited, a mask havingopenings therein is used to define a pattern of conductive features 602,and openings in the mask are filled with a conductive material (e.g.,using an electroless plating process or the like). Subsequently, themask and excess portions of the seed layer are removed, and a dielectricmaterial may be formed around the resulting conductive features 602. Thedielectric material may comprise a same material as bonding layer 118and is also referred to as bonding layer 118 hereinafter.

Next in FIG. 22, dies 102B and 102C are bonded to bonding layer 118using a hybrid bonding process, for example, to formconductor-to-conductor bonds as well as dielectric-to-dielectric bonds.Thus, the need for solder joints (or other external connectors) forbonding dies in embodiment packages is reduced, which reducesmanufacturing defects and cost. Dies 102B and 102C may be substantiallysimilar to die 102A. In a hybrid bonding process, conductive features110B of die 102B and conductive features 110C of die 102C may be alignedand contacted to conductive features 602. ILD/IMD layers 108B and 108Cof dies 102B and 102C, respectively, may also be contacted to bondinglayer 118. Subsequently and anneal may be performed to directly bond theconductive and dielectric materials together. In package 600, conductivefeatures 602 are electrically connected to dies 102B and 102C in orderto provide additional electrical routing for increased circuit designflexibility. For example, conductive features 602 may be used to routeelectrical signals from dies 102B and 102C to another area of package600, such as an area beyond edges of dies 102B and 102C. Thus, routingis not limited to the footprint of dies 102B and 102C, which providesincreased package design flexibility. Conductive features 602 may or maynot electrically connect die 102B to die 102C.

After dies 102B and 102C are bonded to bonding layer 118, an isolationmaterial 120 is formed around dies 102B and 102C as described above.Isolation material 120 may comprise a dielectric material (e.g., anoxide, nitride, oxynitride, or the like), a molding compound, a polymer,or the like. The resulting structure is illustrated in FIG. 23. Althougha non-conformal isolation material 120 is illustrated, in otherembodiments, isolation material 120 may be a conformal layer.

Subsequently, in FIG. 24, additional features are formed in package 600.For example, TVs 124, RDLs 126, UBMs 134, and connectors 132 over dies102A, 102B, and 102C as described above. RDLs 126 may extend past edgesof die 102A onto a top surface of isolation material 116. RDLs 126 maybe electrically connected to die 102A as well as dies 102B and 102C(e.g., by TVs 124). TVs 124 may be formed to contact conductive features602 in bonding layer 118. External connectors 132 are electricallyconnected to dies 102A, 102B, and 102C by RDLs 126.

FIGS. 25A and 25B illustrate cross-sectional views of packages 700A and700B according to some embodiments. Packages 700A and 700B may besimilar to package 600 where like reference numerals indicate likeelements. Packages 700A and 700B include dummy dies 202 adjacent one ormore functional device dies (e.g., dies 102B and 102C) as describedabove. In the embodiment package 700A illustrated by FIG. 25A, dummy die202 has a same thickness as dies 102B/102C. In the embodiment package700B illustrated by FIG. 25B, dummy die 202 has a different thicknessthan dies 102B/102C. Bonding layer 206 may be used to bond dummy dies202 to bonding layer 118 using a fusion bonding process or hybridbonding process, for example. In some embodiments, dummy dies 202 areincluded for improved uniformity in a device layer, which may result inimproved planarization. Dummy dies 202 may also be included to reduceCTE mismatch amongst various features in packages 700A and 700B.

FIGS. 26 through 30 illustrate cross-sectional views of intermediarystages of forming a semiconductor package 800 in accordance with anembodiment. Package 800 in FIG. 26 may be substantially similar topackage 100 in FIG. 2 where like reference numerals indicate likeelements. For example, die 102 may be attached to a carrier 112 by arelease film 114. Release film 114 may comprise a dielectric material(e.g., a buried oxide layer), and release film 114 may comprisealignment marks 802 for improved alignment control for forming variousfeatures of package 800. Alignment marks may be included for improvedaccuracy control during various chip (e.g., die) bonding processes.

Referring next to FIG. 27, an isolation material 116 is formed arounddie 102A, and bonding layers 118 is formed over isolation material 116and die 102A. Dies 102B and 102C are bonded to die 102, for example,using a fusion bonding process with bonding layer 118. An isolationmaterial 120 is formed between dies 102B and 102C. Although anon-conformal isolation material 120 is illustrated, in otherembodiments, isolation material 120 may be a conformal layer. Thevarious process steps for forming isolation material 116, bonding layer118, and isolation material 120 may be similar to the steps describedabove with respect to FIG. 6 and are not discussed further herein forbrevity.

After isolation material 120 is formed, a carrier 122 may be attached toa top surface isolation material 120 by a release layer 123 asillustrated by FIG. 16. In an embodiment, carrier 122 may compriseglass, ceramic, bulk silicon, or the like while release layer 123comprises a DAF, a dielectric material, or the like. After carrier 122is attached, the first carrier 110 may be removed from surfaces of die102A and isolation material 116. Removing carrier 110 may include agrinding process (or other suitable planarization process), which mayfurther remove portions of release film 114 to expose alignment marks802. The resulting structure is illustrated in FIG. 28.

Next in FIG. 29, an orientation of package 500 is reversed so thatpackage 500 is disposed over carrier 122 and release layer 123. Afterpackage 500 is flipped, an additional dielectric material 804 is formedover release layer 114 and alignment marks 802. Subsequently, TVs 124may be formed extending through dielectric material 804, release layer114, isolation material 116, bonding layer 118, and portions of dies102C and 102B. TVs 124 may be electrically connected to conductivefeatures in dies 102B and/or 102C. In some embodiments, forming TVs 124includes a damascene process as described above. In such embodiments, aplanarization process (e.g., CMP, etch back, grinding, or the like) maybe applied so that top surfaces of TVs 124 and dielectric material 804are substantially level.

After TVs 124 are formed, various additional features, such as, RDLs126, UBMs 134, and connectors 132 are formed over dies 102A, 102B, and102C as described above. RDLs 126 may extend past edges of die 102A ontoa top surface of isolation material 116. RDLs 126 may be electricallyconnected to die 102A as well as dies 102B and 102C (e.g., by TVs 124).External connectors 132 are electrically connected to dies 102A, 102B,and 102C by RDLs 126. Carrier 122 may be removed, and the resultingstructure is illustrated in FIG. 30. Alternatively, a portion of carrier122 may remain as a heat dissipation feature.

FIGS. 31 through 35 illustrate cross-sectional views of intermediarystages of forming a semiconductor package 900 in accordance with anembodiment. Package 900 may be similar to package 100 where likereference numerals indicate like elements. As illustrated in FIG. 31,two dies 102A and 102B are attached to a carrier 112 by a release film114. Other embodiments may include any number of dies attached to acarrier. An isolation material 116 is formed around dies 102A and 102Bas described above. Top surfaces of isolation material 116 and dies102A/102B may be substantially level so that conductive features 110Aand 110B as well as ILD/IMD layers 108A and 108B of dies 102A and 102Bare exposed at a top surface of package 900.

Referring next to FIG. 32, a third die 102C is bonded directly to dies102A and 102B without an additional, intermediary bonding layer (e.g.,bonding layer 118, see FIG. 4). Die 102C may be bonded to die 102B and102A using a hybrid bonding process as described above. In the hybridbonding process, conductive features 110C of die 102C are contacted toand directly bonded to conductive features 110A and 110B of dies 102Aand 102C. ILD/IMD layers 108C of die 102C is also contacted and directlybonded to ILD/IMD layers 108A and 108B of dies 102A and 102B. Thus, die102C may be electrically connected to dies 102A and 102B. Furthermore,at least a portion of die 102C may contact isolation material 116, suchas portions of isolation material 116 between dies 102A and 102B. Afterdie 102C is bonded, a thinning process as described above may be appliedso that die 102C is a desired thickness.

Next in FIG. 33, an isolation material 120 is formed around die 102C andover isolation material 116, die 102A, and die 102B. Isolation material120 may be formed of a similar material and using a similar process asdescribed above. Isolation materials 116 and 120 may or may not comprisea same material. Although a non-conformal isolation material 120 isillustrated, in other embodiments, isolation material 120 may be aconformal layer. As further illustrated by FIG. 33, TVs 124 are formedextending through isolation material 120 and optionally portions of dies102A and 102B. TVs 124 may be electrically connected to conductivefeatures 110A and 110B in dies 102A and 102B. In some embodiments, TVs124 may be formed using a damascene process as described above.

In FIG. 34, redistribution lines 902 may be optionally formed overisolation material 120 and TVs 124. Redistribution lines 902 areelectrically connected to TVs 124 in order to route electrical signalsto a desired area of package 900 based on package design. In someembodiments, forming redistribution lines 902 includes depositing a seedlayer (not shown), using a mask layer (not shown) having variousopenings to define the shape of redistribution lines 902, and fillingthe openings in the mask layer using an electro-chemical platingprocess, for example. The mask layer and excess portions of the seedlayer may then be removed.

After redistribution lines 902 are formed, an insulation layer 904(e.g., a dielectric or polymer layer) may be formed aroundredistribution lines 902 as illustrated in FIG. 35. Insulation layer 904may be deposited using any suitable process such as a spin-on process,CVD, PECVD, and the like. Various additional features, such as, RDLs126, UBMs 134, and connectors 132 may also be formed over redistributionlines 902, dies 102A, 102B, and 102C as described above. RDLs 126 mayextend past edges of die 102A over a top surface of isolation material120. RDLs 126 may be electrically connected to die 102A as well as dies102B and 102C (e.g., by TVs 124 and redistribution lines 902). Externalconnectors 132 are electrically connected to dies 102A, 102B, and 102Cby RDLs 126. Carrier 112 may be removed, and the resulting structure isillustrated in FIG. 35.

FIGS. 36A and 36B illustrate cross-sectional views of packages 1000A and1000B according to some embodiments. Packages 1000A and 1000B may besimilar to package 900 where like reference numerals indicate likeelements. Packages 1000A and 1000B include dummy dies 202 adjacent oneor more functional device dies (e.g., dies 102A and 102B) as describedabove. Dummy dies 202 may be included, for example, by attaching dummydies 202 to carrier 112 (see FIG. 31) prior to forming isolationmaterial 116. In the embodiment package 1000A illustrated by FIG. 35A,dummy die 202 has a same thickness as dies 102A/102B. In the embodimentpackage 1000B illustrated by FIG. 35B, dummy die 202 has a differentthickness than dies 102A/102B. In package 1000A, bonding layer 206 maybe used to bond dummy die 202 to die 102C using a fusion bonding processor hybrid bonding process, for example. In package 1000B, a portion ofisolation material 116 may extend over a top surface (e.g., layer 206).In some embodiments, dummy dies 202 are included for improved uniformityin a device layer, which may result in improved planarization. Dummydies 202 may also be included to reduce CTE mismatch amongst variousfeatures in packages 1000A and 1000B.

FIGS. 37 through 42 illustrate cross-sectional views of intermediarystages of forming a semiconductor package 1100 in accordance with anembodiment. Package 1100 may be similar to package 900 where likereference numerals indicate like elements. As illustrated in FIG. 37, adie 102A is attached to a first carrier 112 by a release film 114.Conductive features 110A and ILD/IMD layers 108A of die 102A may beexposed. Die 102A may further include TVs 1102, which may partiallyextend through substrate 104A of die 102A. TVs 1102 may be electricallyconnected to conductive features in die 102A.

As also illustrated by FIG. 37, two dies 102A and 102B are attached to asecond carrier 122 by a release layer 123. Conductive features 110B and110C as well as ILD/IMD layers 108B and 108C of dies 102B and 102C maybe exposed. Carriers 112 and 122 may be used to position dies 102A,102B, and 102C so that a front side of die 102A faces front sides ofdies 102B and 102C. Carriers 112 and 122 may further be positioned so atleast a subset of conductive features 110A, 110B, and 110B are aligned.

Referring next to FIG. 38, dies 102A, 102B, and 102C are bonded using ahybrid bonding process as described above. In the hybrid bondingprocess, conductive features 110A of die 102A are contacted to anddirectly bonded to conductive features 110B and 110C of dies 102B and102C. ILD/IMD layers 108A of die 102A is also contacted and directlybonded to ILD/IMD layers 108B and 108C of dies 102B and 102C. Thus, die102A may be electrically connected to dies 102B and 102C. Subsequently,carrier 122 may be removed.

Next, in FIG. 39, an isolation material 116 is formed around dies 102A,102B, and 102C. In an embodiment, isolation material 116 is a moldingcompound and is formed around dies 102A, 102B, and 102C using a moldingprocess as described above. After isolation material 116 is deposited, aplanarization process (e.g., grinding, CMP, etch back, or the like) maybe applied so that top surfaces of dies 102B and 102C are substantiallylevel.

After isolation material 116 is formed, a third carrier 1104 may beattached to die 102B, die 102C, and isolation material 116 by a releaselayer 1106 as illustrated by FIG. 40. Carrier 1104 and release layer1106 may be substantially similar to carrier 110 and release layer 112as described above. For example, carrier 1104 may comprise glass,ceramic, bulk silicon, or the like while release layer 1106 comprises aDAF, a dielectric material, or the like. After carrier 1104 is attached,the first carrier 112 may be removed from surfaces of die 102A andisolation material 116. Removing the carrier 112 may include applying UVradiation to release layer 114, a mechanical grinding process, an etchback process, combinations thereof, or the like. After carrier 112 isremoved, substrate 104A may also be etched back using a suitable process(e.g., etching, CMP, and the like) to expose TVs 1102. The resultingstructure is illustrated in FIG. 40.

In FIG. 41, TVs 124 are formed extending through isolation material 116and optionally portions of dies 102B and 102C. TVs 124 may beelectrically connected to conductive features 110B and 110C in dies 102Band 102C. In some embodiments, TVs 124 may be formed using a damasceneprocess as described above. Redistribution lines 902 may also beoptionally formed over isolation material 116 and TVs 124 and 1102.Redistribution lines 902 are electrically connected to TVs 124 in orderto route electrical signals to a desired area of package 900 based onpackage design. In some embodiments, forming redistribution lines 902includes depositing a seed layer (not shown), using a mask layer (notshown) having various openings to define the shape of redistributionlines 902, and filling the openings in the mask layer using anelectro-chemical plating process, for example. The mask layer and excessportions of the seed layer may then be removed.

After redistribution lines 902 are formed, an insulation layer 904(e.g., a dielectric or polymer layer) may be formed aroundredistribution lines 902 as illustrated in FIG. 42. Insulation layer 904may be deposited using any suitable process such as a spin-on process,CVD, PECVD, and the like. Various additional features, such as, RDLs126, UBMs 134, and connectors 132 may also be formed over redistributionlines 902, dies 102A, 102B, and 102C as described above. RDLs 126 mayextend past edges of die 102A over a top surface of isolation material120. RDLs 126 may be electrically connected to die 102A (e.g., by TVs1102) as well as dies 102B and 102C (e.g., by TVs 124 and redistributionlines 902). External connectors 132 are electrically connected to dies102A, 102B, and 102C by RDLs 126. Carrier 1104 may be removed, and theresulting structure is illustrated in FIG. 42.

FIGS. 43 through 50 illustrate cross-sectional views of intermediarystages of forming a semiconductor package 1200 in accordance with anembodiment. Package 1200 may be similar to package 1100 where likereference numerals indicate like elements. As illustrated in FIG. 43,dies 102A and 102B are attached to a first carrier 112 by a release film114. Dies 102A and 102B may be disposed so that a front surface isfacedown and contacts release film 114. For example, substrates 104A and104B of dies 102A and 102B, respectively, are exposed in thisorientation. Dies 102A and 102B may further include TVs 1102A and 1102B,respectively. TVs 1102A and 1102B may partially extend through substrate104A of die 102A and substrate 104B of die 102B, respectively. TVs 1102Aand 1102B may be electrically connected to conductive features in dies102A and 102B, respectively.

Next, in FIG. 44, a thinning process is applied to remove portions ofsubstrates 104A and 104B over TVs 1102A and 1102B. The thinning processmay include any suitable planarization process, such as, CMP, grinding,etch-back, and the like. The thinning process exposes TVs 1102A and1102B, and in some embodiments, the thinning process further reduces atotal thickness of dies 102A and 102B to a desired thickness asdescribed above.

Referring next to FIG. 45, an isolation material 116 is formed arounddies 102A and 102B. In an embodiment, isolation material 116 is adielectric material (e.g., an oxide, nitride, oxynitride, and the like),a polymer, or a molding compound as described above. After isolationmaterial 116 is deposited, a planarization process (e.g., grinding, CMP,etch back, or the like) may be applied so that top surfaces of moldingcompound 116, die 102A, and die 102B are substantially level.Subsequently, a dielectric layer 1202 is formed over isolation material116, die 102A, and die 102B. Dielectric layer 1202 may be used toprotect features of dies 102A and 102B during subsequent processing.

In FIG. 46, a second carrier 122 may be attached to dielectric layer1202, die 102A, die 102B, and isolation material 116 by a release layer123. After carrier 122 is attached, the first carrier 112 may be removedfrom surfaces of die 102A, die 102B and isolation material 116. In someembodiments, release layer 114 may remain in package 1200 even aftercarrier 112 is removed. For example, release layer 114 may comprise adielectric material, and carrier 112 may be removed using an etch backprocess, CMP, grinding, or the like.

In FIG. 47, redistribution lines 1204 are formed in release layer 114.Redistribution lines 1204 are electrically connected to conductivefeatures in dies 102A and 102B in order to route electrical signals to adesired area of package 1200 based on package design. In someembodiments, forming redistribution lines 1204 includes depositing aseed layer (not shown), using a mask layer (not shown) having variousopenings to define the shape of redistribution lines 1204, and fillingthe openings in the mask layer using an electro-chemical platingprocess, for example. The mask layer and excess portions of the seedlayer may then be removed.

After redistribution lines 1204 are formed, an additional die 102C isbonded to dies 102A and 102B as illustrated in FIG. 48. In someembodiments, die 102C may be an entire wafer (e.g., prior tosingulation), and dies 102A and 102B may be bonded using a chip on wafer(CoW) bonding process and/or a wafer on wafer (WoW) bonding process. Thewafer may be a re-constructed wafer in an embodiment. The bondingprocess may further include a fusion bonding process as described abovewhere conductive features 110C of die 102C is directly bonded toredistribution lines 1204. The fusion bonding process may furtherinclude directly bonding ILD/IMD layers 108C to release layer 114. Aportion of redistribution lines 1204 (e.g., 1204′) may remain unbondedafter bonding die 102C. Although FIG. 48 illustrates a single die, inother embodiments multiple dies can be attached to dies 102A and 102B.Furthermore, although die 102C is illustrated as spanning an entirewidth of package 1200 (e.g., having sidewalls substantially aligned withsidewalls of isolation material 116), in other embodiments die 102C mayhave a different size. In such embodiments, an isolation material (notshown) may or may not be formed around die 102C.

Subsequently, an orientation of package 1200 is flipped so that dies102A and 102B are disposed over die 102C. Carrier 122 and release layer123 may also be removed as described above. In some embodiments, die102C is used as structural support for further processing to package1200. The resulting package is illustrated in FIG. 49. A cleaningprocess may also be applied to package 1200 after carrier 122 isremoved, and TVs 1102A/112B may be exposed, for example, by removingdielectric layer 1202. As also illustrated in FIG. 49, TVs 124 may beformed extending through isolation material 116 to electrically connectto redistribution lines 1204 (e.g., redistribution line 1204′) inrelease layer 114. In some embodiments, TVs 124 may be formed using adamascene process as described above.

Various additional features, such as, RDLs 126, UBMs 134, and connectors132 may also be formed over dies 102A, 102B, and 102C as describedabove. FIG. 50 illustrates the resulting structure. RDLs 126 may extendpast edges of die 102A over a top surface of isolation material 116.RDLs 126 may be electrically connected to dies 102A and 102B (e.g., byTVs 1102A/1102B) as well as die 102C (e.g., by TVs 124). Externalconnectors 132 are electrically connected to dies 102A, 102B, and 102Cby RDLs 126.

FIG. 51 illustrates a process flow 1300 for forming a semiconductorpackage in accordance with some embodiments. In step 1302, a first die(e.g., die 102A) is attached to a first carrier (e.g., carrier 112). Instep 1304, a first isolation material (e.g., isolation material 116) isformed around the first die. In step 1306, a second die (e.g., die 102Bor 102C) is bonded to the first die. Bonding the second die includes ahybrid bonding or fusion bonding process where adielectric-to-dielectric bond is formed. A conductor-to-conductor bondmay also be formed in some embodiments. The second die may be bonded toa bonding layer formed over the first die and the first isolationmaterial or directly to the first die after the first isolation materialis formed. In step 1308, a second isolation material (e.g., isolationmaterial 120) is formed around the second die. The second isolationmaterial may or may not be a conformal layer, and a third (optional)isolation material may be formed on and contacting the second isolationmaterial. In another embodiment, the second die is bonded to the firstdie directly prior to forming any isolation materials, and then anisolation material may be formed around both the first die and thesecond die simultaneously. After forming the second isolation material,the first carrier may be removed. In step 1310, a through via (e.g., TV124) may be formed extending through the first isolation material andelectrically connected to the second die. In step 1312, fan-out RDLs(e.g., RDLs 126) may be formed on an opposing side of the first die asthe second die. The fan-out RDLs are electrically connected to the firstdie and the second die (e.g., through the through-via).

As described above, embodiment methods and corresponding packagesincludes bonding various dies in a device package using fusion bondingand/or hybrid bonding processes. For example, various embodimentpackages may provide one or more of the following non-limiting features:a CoW structure integrating KGDs, flexible chip size integration,heterogeneous and/or homogeneous multi-chip stacks, and a relativelysmall form factor package. Thus, various embodiments may provide one ormore of the following non-limiting advantages: lower aspect ratio vias,KGD with split or partition chips to reduce manufacturing cost, reduceduse of microbumps or underfill processes for bonding to reducemanufacturing cost thing chip stacking and multi-chip stacking, flexiblechip size stacking, enhanced signal transmission performance, smallerform factor, higher I/O count density, and implementing chip to wafer orwafer to wafer bonding processes.

In accordance with an embodiment, method for forming a semiconductorpackage includes attaching a first die to a first carrier, depositing afirst isolation material around the first die, and after depositing thefirst isolation material, bonding a second die to the first die. Bondingthe second die to the first die includes forming adielectric-to-dielectric bond. The method further includes removing thefirst carrier and forming fan-out redistribution layers (RDLs) on anopposing side of the first die as the second die. The fan-out RDLs areelectrically connected to the first die and the second die.

In accordance with another embodiment, a method includes attaching afirst die to a first carrier, forming a first isolation materialextending along sidewalls of the first die, and forming a bonding layerover the first die and the first isolation material. The method furtherincludes bonding a second die directly to the bonding layer, forming asecond isolation material extending along sidewalls of the second die,and attaching a second carrier over the second die. The method alsoincludes removing the first carrier, forming a through via extendingthrough the first isolation material and electrically connected to thesecond die, and forming fan-out redistribution layers (RDLs) on anopposing side of the first die as the second die. The fan-out RDLs areelectrically connected to the first die and the through via.

In accordance with yet another embodiment, a semiconductor packageincludes a first die, a first isolation material disposed around thefirst die, a bonding layer over the first die and the first isolationmaterial, and a second die directly bonded to the bonding layer. Thesecond die includes a conductive feature disposed in a dielectric layer.The package further includes a second isolation material disposed aroundthe second die, a through via extending through the first isolationmaterial and the bonding layer to contact the conductive feature in thesecond die, and fan-out redistribution layers (RDLs) on an opposing sideof the first die as the second die. The fan-out RDLs are electricallyconnected to the first die and the through via

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A package comprising: a first semiconductor die;a second semiconductor die bonded to the first semiconductor die,wherein a first dielectric layer of the first semiconductor die isdirectly bonded to a second dielectric layer of the second semiconductordie; a third semiconductor die bonded to the first semiconductor die,wherein the first dielectric layer of the first semiconductor die isdirectly bonded to a third dielectric layer of the third semiconductordie; a first isolation material disposed around the second semiconductordie and the third semiconductor die, wherein the second semiconductordie is physically separated from the third semiconductor die by thefirst isolation material; and a redistribution structure electricallyconnected to the first semiconductor die, the second semiconductor die,and the third semiconductor die.
 2. The package of claim 1, wherein theredistribution structure is disposed on an opposing side of the firstsemiconductor die as the second semiconductor die and the thirdsemiconductor die.
 3. The package of claim 1, wherein the redistributionstructure is electrically connected to the second semiconductor die by aconductive via extending through a second isolation material, andwherein the first semiconductor die is physically separated from theconductive via by the second isolation material.
 4. The package of claim3, wherein the second isolation material is disposed around the firstsemiconductor die.
 5. The package of claim 1 further comprising a dummydie surrounded by the first isolation material.
 6. The package of claim5, wherein the dummy die is disposed between the second semiconductordie and the third semiconductor die.
 7. The package of claim 5, whereina fourth dielectric layer of the dummy die is directly bonded to thefirst dielectric layer of the first semiconductor die.
 8. The package ofclaim 5, wherein the dummy die is physically separated from the secondsemiconductor die by the first isolation material.
 9. The package ofclaim 1, wherein a first contact pad in the first dielectric layer isdirectly bonded to a second contact pad in the second dielectric layer.10. The package of claim 1, wherein the first semiconductor die extendscontinuously from the second semiconductor die to the thirdsemiconductor die.
 11. A semiconductor package comprising: a firstsemiconductor die; a second semiconductor die, wherein a firstdielectric layer of the first semiconductor die is directly bonded to asecond dielectric layer of the second semiconductor die, and wherein afirst contact pad the first semiconductor die is directly bonded to asecond contact pad of the second semiconductor die; an isolationmaterial disposed around the first semiconductor die and the secondsemiconductor die; a redistribution structure on an opposing side of thefirst semiconductor die as the second semiconductor die, wherein theredistribution structure is electrically connected to the firstsemiconductor die; and a first conductive via electrically connectingthe redistribution structure to the second semiconductor die, whereinthe first conductive via is laterally separated from the firstsemiconductor die.
 12. The semiconductor package of claim 11, whereinthe first conductive via extends to a third contact pad of the secondsemiconductor die, wherein the third contact pad and the second contactpad are disposed at a surface of the second dielectric layer, andwherein the surface of the second dielectric layer faces the firstsemiconductor die.
 13. The semiconductor package of claim 11 furthercomprising a third semiconductor die laterally separated from the secondsemiconductor die, wherein a third dielectric layer of the thirdsemiconductor die is directly bonded to the first dielectric layer, andwherein a fourth contact pad of the third semiconductor die is directlybonded to a fifth contact pad of the first semiconductor die.
 14. Thesemiconductor package of claim 13 further comprising a second conductivevia electrically connecting the redistribution structure to the thirdsemiconductor die, wherein the second conductive via is laterallyseparated from the first semiconductor die.
 15. The semiconductorpackage of claim 14, wherein the first conductive via and the secondconductive via are disposed on opposing sides of the first semiconductordie.
 16. The semiconductor package of claim 13, wherein the firstsemiconductor die extends from the second semiconductor die to the thirdsemiconductor die.
 17. A method comprising: encapsulating a firstsemiconductor die and a second semiconductor die in a first isolationmaterial; bonding a third semiconductor die to the first semiconductordie and the second semiconductor die by directly bonding a firstdielectric layer of the first semiconductor die to a third dielectriclayer of the third semiconductor die and by directly bonding a seconddielectric layer of the second semiconductor die to a third dielectriclayer of the third semiconductor die; and forming a redistributionstructure electrically connected to the first semiconductor die, thesecond semiconductor die, and the third semiconductor die.
 18. Themethod of claim 17 wherein the third semiconductor die is bonded to thefirst semiconductor die and the second semiconductor die afterencapsulating the first semiconductor die and the second semiconductordie, and wherein the method further comprises encapsulating the thirdsemiconductor die in a second isolation material after bonding the thirdsemiconductor die to the first semiconductor die and the secondsemiconductor die.
 19. The method of claim 17 further comprisingencapsulating a dummy die in the first isolation material.
 20. Themethod of claim 17 further comprising forming a conductive viaelectrically connecting the second semiconductor die to theredistribution structure.